Treating "incurable" cancer by targeting genes rather than where the disease is located in the body can "transform" survival chances and give years of extra life, a major new study has found.

The first long-term analysis of patients with difficult-to-treat tumours who underwent gene testing has shown the personalised technique boosted chances of surviving 10 years by a factor of six compared to standard practice.

Oncology experts last night called for all cancer patients to be provided "next generation sequencing" in order to identify the drug which works best personally for them.

Doctors at the University of Texas analysed the progress of 1,307 patients with a range of cancers including breast, gynecologic and gastrointestinal.

Of these, 711 were then tested to determine the precise molecular abnormalities of their tumour and assigned to the most appropriate clinical drug trial.

Benefit

Presented at the American Society for Clinical Oncology (Asco) meeting in Chicago, the study showed that 15pc of those who underwent matched therapy survived for three years compared to 7pc of patients who had unmatched therapy, while 6pc of the matched group survived 10 years compared to 1pc unmatched.

While overall survival was small in the study because the patients were so ill to start with, the scientists behind it said the relative benefit of matched therapy applies to all cancer patients.

"All patients should have access to next generation sequencing and I believe in the next few years we are going to see this approach dramatically improving outcomes," said Professor Apostolia Maria Tsimberidou, who led the research.

"We need to know what is really causing these diseases so we can treat them properly."

Professor Tsimberidou said personalised cancer medicines had kept one patient alive in her clinic since 2011 despite suffering from glioblastoma, the aggressive brain cancer which killed former British cabinet minister Tessa Jowell last month.

Dr Catherin Diefenbach, an Asco expert, said scientists had barely "scratched the surface" of the potential of precision medicine.

"Now with faster and more robust genetic tests, we can help even more patients by treating the cancer based on its genetic make-up rather than solely on its location in the body," she said.

The new study is the first to directly compare the impact of precision medicine against traditional approaches across many different cancer types for a long period.